1. Field of the Invention
This invention relates to the dyeing of keratinous materials. More particularly, it relates to coloring compositions for producing a semi-permanent dyeing of hair for cosmetic purposes. The dyeing of the hair is accurately reproducible, nonstaining to the skin and is advantageously accomplished by directly applying the coloring composition of this invention to the hair at normal room temperature.
2. Description of the Prior Art
Coloring preparations for modifying or changing the natural hair color may be classed generally into the permanent colors and the temporary colors. In current practice permanent colors are oxidation dyes based on certain coal tar intermediates which develop color in the presence of an oxidizing agent such as hydrogen peroxide in an alkaline solution. The permanent colors are retained by the hair until the hair grows out, although the original shade may become altered as the result of frequent shampooing, perspiration, exposure to light, use of permanent waves or other chemical hair treatments.
The temporary colors are used to give color highlights to the hair, to correct yellowish streaks in gray hair, to blend in mixed gray hair and to brighten and intensify the natural hair color.
The temporary dyes are of several different types. There are acid dyes in conjunction with organic acids such as citric and tartaric, and sometimes with a surfactant. Another type is the cationic or basic dyes combined with buffering salts such as borates, citrates or phosphates. Still another type comprises the complex dyes which are formed by the interaction of acid dyes (including direct dyes) with cationic surfactants.
The dyes of all these types of temporary dyes impart color to the hair by way of forming a film on the hair surface. These films are of varying durability. Thus, the first-mentioned type, the acid dyes, can be completely removed by a single shampooing, while the second-mentioned type, the buffering cationic or basic dyes, usually last through a few shampooings.
In recent years, a demand has been created for hair colors of the temporary type--which do not require irritating oxidative dyes or high temperatures as is the case for some permanent colors--but which as well would provide a hair coloring with longer-lasting characteristics, in effect, a hair coloring which will withstand many shampoo treatments and will be semipermanent in its lasting properties. The present invention is directed towards fulfilling this need.